1. Technical Field
The present disclosure relates to a method and arrangement for identifying a difference between a first 3D model of an environment and a second 3D model of the environment. In particular, the present disclosure relates to identifying a difference, wherein the first and second 3D model each comprise a plurality of points or parts, and wherein each point or part of the first and second model comprises geometrical information and texture information
The present disclosure also relates to a method and arrangement for identifying a difference between a 3D model of an environment and the environment as reproduced at another timing. In particular, the present disclosure relates to identifying a difference, wherein said reproduction of the environment comprising at least one 2D image, and wherein each point or part of the first 3D model comprises geometrical and texture information
2. Description of Related Art
A fast growing market both in civilian and military business is geographical information systems. Knowledge about geographical conditions forms a fundamental decision support to companies, authorities and in the military. The geographical information can comprise digital maps having superposed information layers such as infrastructure, terrain type and different types of objects. This way of providing digital maps is time consuming and comprises forming two dimensional maps comprising capturing images of the terrain from an aircraft and post-processing of the captured images. It is an even more time consuming process to form three dimensional maps from captured images or range data sets of the terrain/infrastructure.
WO 2009/003529 relates to another type of geographical information system. It relates to an arrangement and a method for providing a three dimensional map representation of an area. The arrangement comprises a processing unit arranged to, for a plurality of time recorded, overlapping images of the area to be stereo processed, associate navigation states so that each pixel of each time recorded image is correlated to a corresponding navigation state and to perform the stereo processing based on the associated navigation states that all pixels in the map representation are specified in three geographical dimensions.
It is desirable to detect changes in the environment. These changes can be due natural variations like flooding, earthquakes, moving glaciers, falling rocks, erosions, or the like. They can also be due to growing plants or trees, due to different seeds on fields or the like. They can also be due to human made interactions like construction working (for example for building infrastructure, buildings, etc. . . . ), removing or destroying of constructions (for example, due to war, due to fire, due to forces of nature, due to dismantling or demolishing of buildings, constructions for other purposes, etc.).
For detecting these changes, a common way is to compare maps or images. This is often done in a manual way to find differences between them. This is a time-consuming task.